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Old 01-28-2015, 10:46 AM
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Hey guys!

So I finally got my Harbor Freight Predator 420cc engine mounted on my go kart. (pics coming soon!!!) Aside from hacksawing off part of my frame, it was pretty easy

Anyway, I slapped on an old exhaust header from a different build that I never used...

First start... fing LOUD. Like ....ears ringing for hours afterwards (just sitting at idle)

Here's a link to the ebay seller where I bought it: http://www.ebay.com/itm/Engine-Heade...item3f42ac6bc2

Gonna go buy some ear plugs now...

Sorry
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Old 01-28-2015, 11:07 AM
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Been looking at exhaust like that was wondering just how loud they would be.
Cole
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Old 01-28-2015, 01:17 PM
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What did you say?....What!?!?

I am in the wrong business. I made two headers all most identical to that for around $4, LOL

Can't wait to see yours in action!
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Old 01-28-2015, 02:10 PM
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Quote:
Originally Posted by crankshaft View Post
Hey guys!

So I finally got my Harbor Freight Predator 420cc engine mounted on my go kart. (pics coming soon!!!) Aside from hacksawing off part of my frame, it was pretty easy

Anyway, I slapped on an old exhaust header from a different build that I never used...

First start... fing LOUD. Like ....ears ringing for hours afterwards (just sitting at idle)

Here's a link to the ebay seller where I bought it: http://www.ebay.com/itm/Engine-Heade...item3f42ac6bc2

Gonna go buy some ear plugs now...

Sorry
there is prob nothing to slow the exhaust down (somthing inside to damper the exhaust or slow things down ) the exhaust i had on my mini cup had what looked like mesh inside
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Old 01-28-2015, 03:04 PM
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there is prob nothing to slow the exhaust down (somthing inside to damper the exhaust or slow things down ) the exhaust i had on my mini cup had what looked like mesh inside
I'm fairly certain there's no baffle in this pipe; it's just made to look like a muffler. Seems like solid construction; I just felt bad for my neighbors

It was cheaper when I bought it... I guess demand might have gone up since there's not a ton of places to buy headers specifically for the 420cc
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Old 01-28-2015, 03:06 PM
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I know what you mean, I've been starting my 600cc 4 cylinder with straight pipes and it definately wakes you up
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Old 01-28-2015, 03:35 PM
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(so basically you would be better off just using nothing because the muffler is doing nothing but making noise and looking good (for looks) A exhaust on a 4 stroke with just a little bit of restriction little is a lot better then no exhaust at all and better then a exhaust that restricts to much but the exhaust you have is not doing anything
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Old 01-28-2015, 03:59 PM
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(so basically you would be better off just using nothing because the muffler is doing nothing but making noise and looking good (for looks) A exhaust on a 4 stroke with just a little bit of restriction little is a lot better then no exhaust at all and better then a exhaust that restricts to much but the exhaust you have is not doing anything
Yep. I'm probably going to put the stock air box back on for now. The header does look good though
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Old 01-28-2015, 04:00 PM
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I know what you mean, I've been starting my 600cc 4 cylinder with straight pipes and it definately wakes you up
I got a ticket for straight pipes on a CBR600 a few years back
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Old 01-28-2015, 04:21 PM
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I got a ticket for straight pipes on a CBR600 a few years back
Dont worry if it helps i got a ticket for riding my motorized bike in the bike lane on saturday doing the speed limit going to church
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Old 01-28-2015, 04:25 PM
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Yeah, that's, pretty much, just a straight pipe; the larger bore tail piece produces a lower note than the small bore pipe
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Old 01-28-2015, 05:21 PM
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Quote:
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Yeah, that's, pretty much, just a straight pipe; the larger bore tail piece produces a lower note than the small bore pipe
Is it correct that all engines need some restriction to function 100%
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Old 01-28-2015, 06:38 PM
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Short answer, yes; for the in-depth explanation, read this
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Old 01-29-2015, 09:04 AM
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Quote:
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Is it correct that all engines need some restriction to function 100%
I was reading an artical a while back and it was talking about how you need to find the right exhaust tube diameter for your application. If you have a smaller diameter exhaust, it will create more backpressure but will create more velocity, velocity helps act kind of like a vacuum and actually helps pull even more exhaust out, but that benefit is counteracted with increased back pressure. So when someone puts a huge 4" exhaust on their prius , they actually hurt performance. with a larger exhaust, the low end power suffers (if I'm not mistaken) but in the higher rpms, you typically put out higher numbers than stock (not always the case). So, in summary, you need to find the right balance for your engine and where you're looking to get your power. This is the reason top fuel dragsters and such all are open headers becuase they scream at WOT at all times so the backpressure buildup would be immense.
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Old 01-29-2015, 09:09 AM
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Quote:
Originally Posted by BirdFanatic View Post
(so basically you would be better off just using nothing because the muffler is doing nothing but making noise and looking good (for looks) A exhaust on a 4 stroke with just a little bit of restriction little is a lot better then no exhaust at all and better then a exhaust that restricts to much but the exhaust you have is not doing anything
Not quite..... You need an exhaust pipe to help carry the heat away from the head, otherwise, you'll end up burning up a valve. Running nothing at all is NO good. Even a piece of tube 4" long is better than nothing.....
Justins exhaust sounds pretty good. He said he will post a sound clip of his $4 exhaust to compare to yours..... ( Yes, I'm ing up a sound off...... ).......
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Old 01-29-2015, 10:03 AM
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I was wondering why my ears were burning.... I will try to post them, been having issues here lately with videos.

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Old 01-29-2015, 10:08 AM
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Got some sparks shooting out of your clutch in the 2nd vid.. Chain rub?
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Old 01-29-2015, 10:11 AM
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That's for night riding
Yep it was rubbing but its all fixed now.
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Old 01-29-2015, 10:25 AM
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I think I just figured out how to post on youtube and make these work better(I am not much on these computers,lol)
My son's cart


My new header I have just made(motor is not right yet so its not running the best at this time, hope to cure that this evening)


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Old 01-29-2015, 12:05 PM
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I'll record mine again, tonight,when I get home.
Sounds/looks good ,Justin
EDIT
Whoa! Sounds better in the second video!!
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